Usually, intravenous infusion makes use of a large volume of fluid so that completing that procedure requires long tiring hours. In the general case, a nurse or hospital orderly departs just after the beginning of intravenous infusion is started and returns only one or two times to see the progressing condition. If there is some other thing distracting the nurse's attention and a failure to attend before fluid depletion, there is very likely to be air entering the vessel to endanger the patient. That possibility is a cause of fear, leading patients to keep awake as much as they can, consistently watching the fluid bottle, no matter how tired they feel and require a good rest or sleep.